Book excerpt: The Advanced Study Institute (ASI) under discussion was initiated by the "Special Programme Panel on Radio meteorology" of the Scientific Affairs Division of NATO. The domain of this panel - and consequently the topics of their former ASI-~rogrammes - is the influ ence of the non-ionized atmosphere on electromagnetic wave propagation, its prediction and its use as a re mote sensing technique. It is the final goal to inform radio and radar engineers about the various defects caused by the propagation medium atmosphere. Today there exist high-sensitive radar systems which can pro vide identification and produce images of distant ob jects very accurately by measuring a) the effect of the target on the shape of a short radar pulse, or b) the wave front (phase and amplitude distribution) and its orientation in space. But usuallv the radar-to-target path is through the inhomogeneous and turbulent atmo sphere and so the absolut limits of the system are very often determined by this atmosphere. It was the plan of this ASI to arrange an interdisciplinary information exchange between radar experts and propagation specia lists in order to get a better understanding of the susceptibility to atmospheric effects and to develope new methods that will reduce or correct these errors. The lectures given and especially the intensive dis cussions during the workshop sessions contributed to this aim.